The National Transportation Safety Board has released their preliminary report into the deadly midair collision between an American Airlines flight and a U.S. Army Black Hawk helicopter over Washington,

The National Transportation Safety Board uncovered more than 15,000 “near-miss events” between helicopters and jets at Reagan National airport in just three years leading up to the American Airlines jet and Army helicopter collision that killed 67 people.

The National Transportation Safety Board on Tuesday released two reports — one on preliminary findings and another on safety recommendations — related to the deadly collision of an Army Black Hawk helicopter and an American Airlines regional jet in January. The crash killed 67 people.